TY - JOUR
T1 - Cardiopulmonary baroreflex is reset during dynamic exercise
AU - Ogoh, Shigehiko
AU - Brothers, R. Matthew
AU - Barnes, Quinton
AU - Eubank, Wendy L.
AU - Hawkins, Megan N.
AU - Purkayastha, Sushmita
AU - O-Yurvati, Albert
AU - Raven, Peter B.
PY - 2006/1
Y1 - 2006/1
N2 - The purpose of this study was to examine the hypothesis that the operating point of the cardiopulmonary baroreflex resets to the higher cardiac filling pressure of exercise associated with the increased cardiac filling volumes. Eight men (age 26 ± 1 yr; height 180 ± 3 cm; weight 86 ± 6 kg; means ± SE) participated in the present study. Lower body negative pressure (LBNP) was applied at 8 and 16 Torr to decrease central venous pressure (CVP) at rest and during steady-state leg cycling at 50% peak oxygen uptake (104 ± 20 W). Subsequently, two discrete infusions of 25% human serum albumin solution were administered until CVP was increased by 1.8 plusmn; 0.6 and 2.4 ± 0.4 mmHg at rest and 2.9 ± 0.9 and 4.6 ± 0.9 mmHg during exercise. During all protocols, heart rate, arterial blood pressure, and CVP were recorded continuously. At each stage of LBNP or albumin infusion, forearm blood flow and cardiac output were measured. During exercise, forearm vascular conductance increased from 7.5 ± 0.5 to 8.7 ± 0.6 U (P ± 0.024) and total systemic vascular conductance from 7.2 ± 0.2 to 13.5 ± 0.9 l·min -1·mmHg -1 (P < 0.001). However, there was no significant difference in the responses of both forearm vascular conductance and total systemic vascular conductance to LBNP and the infusion of albumin between rest and exercise. These data indicate that the cardiopulmonary baroreflex had been reset during exercise to the new operating point associated with the exercise-induced change in cardiac filling volume.
AB - The purpose of this study was to examine the hypothesis that the operating point of the cardiopulmonary baroreflex resets to the higher cardiac filling pressure of exercise associated with the increased cardiac filling volumes. Eight men (age 26 ± 1 yr; height 180 ± 3 cm; weight 86 ± 6 kg; means ± SE) participated in the present study. Lower body negative pressure (LBNP) was applied at 8 and 16 Torr to decrease central venous pressure (CVP) at rest and during steady-state leg cycling at 50% peak oxygen uptake (104 ± 20 W). Subsequently, two discrete infusions of 25% human serum albumin solution were administered until CVP was increased by 1.8 plusmn; 0.6 and 2.4 ± 0.4 mmHg at rest and 2.9 ± 0.9 and 4.6 ± 0.9 mmHg during exercise. During all protocols, heart rate, arterial blood pressure, and CVP were recorded continuously. At each stage of LBNP or albumin infusion, forearm blood flow and cardiac output were measured. During exercise, forearm vascular conductance increased from 7.5 ± 0.5 to 8.7 ± 0.6 U (P ± 0.024) and total systemic vascular conductance from 7.2 ± 0.2 to 13.5 ± 0.9 l·min -1·mmHg -1 (P < 0.001). However, there was no significant difference in the responses of both forearm vascular conductance and total systemic vascular conductance to LBNP and the infusion of albumin between rest and exercise. These data indicate that the cardiopulmonary baroreflex had been reset during exercise to the new operating point associated with the exercise-induced change in cardiac filling volume.
KW - Blood pressure
KW - Central blood volume
KW - Forearm blood flow
UR - http://www.scopus.com/inward/record.url?scp=33644817770&partnerID=8YFLogxK
U2 - 10.1152/japplphysiol.00804.2005
DO - 10.1152/japplphysiol.00804.2005
M3 - Article
C2 - 16150844
AN - SCOPUS:33644817770
SN - 8750-7587
VL - 100
SP - 51
EP - 59
JO - Journal of Applied Physiology
JF - Journal of Applied Physiology
IS - 1
ER -